For the shortcrust pastry, knead the flour, margarine, sugar and egg. Line the bottom and the edge of a prepared springform pan with the batter.
For the filling, cut the rhubarb into small pieces and place on the shortcrust pastry. Mix the sour cream with sugar, vanilla pudding powder and egg yolk and pour the mixture over the rhubarb.
Bake the cake in a preheated oven at 180 ° C for approx. 30 - 40 minutes.
Beat the egg whites until stiff and let the sugar trickle in.
After about 40 minutes of baking time, depending on the oven, remove the cake and place the meringue on top of the cake.
Turn the oven back to 150 ° C and bake the cake for another 10 minutes.